In this paper, a control law to stabilize the amplitude or rotational speed of a variable length pendulum to a desired value by periodically changing the position of the center of gravity is ...proposed. First, the motion of the pendulum oscillating around a lower equilibrium point is analyzed using the averaging method, and a first-order differential equation for the amplitude of the pendulum is derived. Subsequently, using the derived equation of motion, a control law is designed to control the amplitude of the pendulum to the desired value. Similarly, the motion of a pendulum rotating continuously around the rotation axis is analyzed, the first-order differential equation for the angular velocity of the pendulum is derived, and then a control law of the rotational speed is designed. The derived nonlinear feedback control law consists of the amplitude, angle, and angular velocity of the pendulum in the case of amplitude control, and in the case of rotational speed control, the rotational velocity and angular acceleration of the pendulum. Finally, by using the proposed control method, it is shown that the amplitude and rotational speed of the pendulum can be controlled to the desired values.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper presents an ANN-based rotational speed control to avoid the stalling behavior in Oscillating Water Columns composed of a Doubly Fed Induction Generator driven by a Wells turbine. This ...control strategy uses rotational speed reference provided by an ANN-based Maximum Power Point Tracking. The ANN-based MPPT predicts the optimal rotational speed reference from wave amplitude and period. The neural network has been trained and uses wave surface elevation measurements gathered by an acoustic Doppler current profiler. The implemented ANN-based rotational speed control has been tested with two different wave conditions and results prove the effectiveness of avoiding the stall effect which improved the power generation.
•The rotational speed control system of the water-driven spindle was designed in the present paper.•The designed feedback control system can reduce the change in the spindle speed due to the cutting ...forces.•The disturbance observer was added into the feedback control system.•The influence of cutting force on spindle speed can be minimized the designed control system with disturbance observer.
The water driven spindle has been developed for use in an ultra-precision machine tool for producing precision parts. In order to achieve high machining accuracy and generate high-quality surfaces, precise rotational accuracy and a constant machine tool spindle speed are necessary in ultra-precision machine tools. However, the rotational speed of the spindle inevitably changes due to the influence of the cutting forces during machining process. In order to deal this problem, this paper describes the development of a rotational speed control system. In particular, the control system is designed such that the influence of the cutting forces is effectively reduced. In this paper, mathematical models of the water-driven spindle and the flow control valve are introduced to develop a feedback control system. The effectiveness of the developed feedback control system is then verified through simulation and experimental tests. In addition, the disturbance observer is added to the designed feedback control system in order to minimize the influence of the cutting forces. Turning tests are then carried out in order to verify the effectiveness of the disturbance observer. As a results, the developed feedback control system with the disturbance observer is verified to successfully reduce the change in the rotational speed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Recycling of lithium-ion batteries will become imperative in the future, but comprehensive and sustainable processes for this are still rather lacking. Direct recycling comprising separation of the ...black mass components as a key step is regarded as the most seminal approach. This paper contributes a novel approach for such separation, that is fractionation in a tubular centrifuge. An aqueous dispersion of cathode materials (lithium iron phosphate, also referred to as LFP, and carbon black) serves as exemplary feed to be fractionated, desirably resulting in a sediment of pure LFP. This paper provides a detailed study of the commonly time-dependent output of the tubular centrifuge and introduces an approach aiming to achieve constant output. Therefore, three different settings are assessed, constantly low, constantly high and an increase in rotational speed over time. Constant settings result in the predictable unsatisfactory time-variant output, whereas rotational speed increase proves to be able to maintain constant centrate properties. With further process development, the concept of fractionation in tubular centrifuges may mature into a promising separation technique for black mass in a direct recycling process chain.
Rotary steering systems are cutting-edge, intelligent oil drilling and steering equipment developed at the end of the twentieth century. The core function of the bit pointing rotary steering system ...is to control the eccentric shaft with bit pointing function to track the outer drill collar for reverse rotation
. When the relative speed thereof is offset, the mandrel tool face remains stationary, and the directive function of the drill bit is realized
. Therefore, it is important to precisely control mandrel rotational speed and make it follow the outer drill collar to conduct face-to-face rotation at all times. A double closed loop control method for realizing rotational speed loop and position loop through controlling mandrel rotational speed is proposed in this paper. Relative rotational speed of drill bit shaft (or mandrel) and drill collar of zero can be realized within the shortest time, thereby realizing rapid and precise rotational speed tracking. Relative positions of mandrel and drill collar at several angles on 360° circumferences, thereby proving the feasibility of the method. The method can provide a technical reference and basis for prototype production of directional rotary steering system
.
Guide vane closure scheme (GVCS) optimisation in hydroturbine generating unit (HTGU) under extreme conditions is one of the most important issues in hydropower plant design and operation. It is a ...kind of multiobjective constrained optimisation problem that contains the coordination of hydraulic and mechanical dynamic processes of many system states. In such a problem, the traditional optimisation objectives often include the control of the rotational speed of the HTGU and the suppression of the fluctuation amplitudes of the hydraulic pressure at different locations. In order to improve the overall control performances in load rejection process, an improved multi-objective two-archive evolutionary algorithm (TAEA) is put forward for GVCS with chaotic operators. The TAEA-based multi-objective optimisation carefully takes the multiple objective functions and the relevant constraint treatments including the limits on rotational speed peak, speed fluctuations, surge tank water levels, speed governor movement and hydraulic pressure oscillations into consideration. Simulation experiments of a real hydroturbine unit under load rejection condition are conducted with the proposed optimisation scheme and comparative methods. The results indicate that TAEA algorithm can achieve better overall performances and contribute to the operational stability of HTGU.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Based on 19 high-quality articles, this Special Issue presents methods for further improving the currently achievable recycling rate, product quality in terms of focused elements, and approaches for ...the enhanced mobilization of lithium, graphite, and electrolyte components. In particular, the target of early-stage Li removal is a central point of various research approaches in the world, which has been reported, for example, under the names early-stage lithium recovery (ESLR process) with or without gaseous CO2 and supercritical CO2 leaching (COOL process). Furthermore, many more approaches are present in this Special Issue, ranging from robotic disassembly and the dismantling of Li‐ion batteries, or the optimization of various pyro‐ and hydrometallurgical as well as combined battery recycling processes for the treatment of conventional Li‐ion batteries, all the way to an evaluation of the recycling on an industrial level. In addition to the consideration of Li distribution in compounds of a Li2O-MgO-Al2O3-SiO2-CaO system, Li recovery from battery slags is also discussed. The development of suitable recycling strategies of six new battery systems, such as all-solid-state batteries, but also lithium–sulfur batteries, is also taken into account here. Some of the articles also discuss the fact that battery recycling processes do not have to produce end products such as high-purity battery materials, but that the aim should be to find an “entry point” into existing, proven large-scale industrial processes. Participants in this Special Issue originate from 18 research institutions from eight countries.
Transporting industry is having an important influence on the nations’ progress. The states that having long shoreline are taking advantage of their locations in using sea transportations which is ...more economical than other types of transportations. One of the most economical marine transport is the diesel fueling engines. This paper is to optimize the PID controller to control the speed of the engine overcoming the navigation environmental changes such as waves, winds and other effective external factors as well as the vessel internal changes such as the shipment load, equipment’s conditions …etc. PID is optimized through the optimum selection of its parameters (KP, KI and KD). A Simulink/MatLab model of the system is designed for this purpose. The Hybrid IWOPSO (HIWOPSO) algorithm is used for finding the optimum values of the PID parameters. The engine step response with these parameters is compared to the responses with those obtained by the IWO and PSO besides the Fuzzy Logic Control (FLC).
The directly-driven variable speed constant frequency wind power generation system, which consists of the permanent magnet synchronous generator (PMSG), is connected to the grid by full size power ...converters. When severe faults occur in grid, the faults would not only cause serious damage to HVDC devices, but also have an adverse impact on the stable operation of overall wind power generation system. The disability mechanism of DC voltage during faults is analyzed. Based on the inertial energy storage characteristics of PMSG rotor and the reactive power compensation capability of grid-side converter, a novel coordinated control strategy aimed at improving the fault ride-through capability of PMSG is proposed. In order to decrease the imbalance power injected to the DC-link and suppress the overvoltage of DC-link, the proposed control strategy adopts an optimal generator-side segmented rotor speed controller to adjust the active power from wind turbine and increase the reactive power to grid on the basis of th
Magnetorheological Transmission for Total Artificial Heart KITAYAMA, Fumiya; MASUZAWA, Toru; OSA, Masahiro ...
Journal of the Japan Society of Applied Electromagnetics and Mechanics,
2023, 2023-00-00, Volume:
31, Issue:
2
Journal Article
Open access
We proposed a new transmission to control the flow difference between left and right pumps in total artificial hearts. The transmission consists of input and output shafts, magnetorheological fluid, ...and electromagnets with adjustable current and position. A motor rotates the input shaft of the transmission. The transmission transfers the torque to the output shaft that rotates with decelerated rotational speed according to the flow resistance of the magnetorheological fluid. First, we measured the output rotational speed when load torque is 5 mNm, and the input rotational speed was 2000 rpm. The rotational speed difference between input and output shafts changed from 450 rpm to 6 rpm when we increased the electromagnet current from 0.4 to 0.55 A. The difference changed from 2 rpm to 219 rpm when we moved the electromagnet position from 2 to 9 mm. Also, we analyzed that magnetic flux density distribution change according to the current or electromagnet position by 3D computational magnetic field analysis. These results show that magnetic flux density distribution affects the output rotational speed. The yield stress is identified based on the measured and analyzed results. In this paper, we show that the developed transmission is enough small and has sufficient transmission performance.
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